Turning Coke Oven Gas into Baking Powder
Making cookies from coal? In theory it is now possible with a completely new technology developed in a collaborative project by the Schwelgern coke plant (KBS), plant engineering company ThyssenKrupp Industrial Solutions and TU Berlin. A pilot plant installed on the works site of ThyssenKrupp Steel Europe in Duisburg produces a substance – ammonium bicarbonate – that can actually be used as baking powder. But the idea behind the project is not to enter the food industry; the main aim of the pilot plant is to convert process gases generated during the production of coke into marketable materials such as fertilizers and chemical propellants. As an added bonus, it reduces CO2 emissions. The plant is the first of its kind worldwide. The new process starts with the production of coke, alongside iron ore the most important charge material for producing pig iron in the blast furnace. The hot gases generated by this process contain a number of substances. The pilot plant uses a complex process to scrub the coke oven gas. Adding carbon dioxide produces ammonium bicarbonate. The end products can be put to a range of uses: as nitrogen fertilizers, as propellants and foaming agents for plastics or porous ceramics, and also in the food industry. Following successful tests in the laboratory, two researchers from TU Berlin were tasked with building the pilot plant in Duisburg. As part of ThyssenKrupp Steel Europe’s integrated iron and steel mill in Duisburg, the Schwelgern coke plant offers ideal conditions for the test phase. Initial results have been promising: 95 % of the ammonia contained in the coke oven gas was utilized. Every hour the process produces 15 kg of solid materials from 15 m3 of coke oven gas and 2 m3 of carbon dioxide. With this level of efficiency, the chemical products can be manufactured at competitive costs. Schwelgern coke plant produces 2,6 Mt/a of fuel for the blast furnaces in Duisburg. It is the most modern of its kind in Europe and boasts the world’s biggest ovens. It currently employs around 300 people and is operated by Betriebsführungsgesellschaft Kokereibetriebsgesellschaft Schwelgern GmbH (KBS), a subsidiary of ThyssenKrupp Steel Europe.